74 RHODA ERDMANN AND LORANDE L. WOODRUFF 



occurs, as is the case in the description of this phase in the 

 conjugation of Paramaecium caudatum as worked out by Cal- 

 kins and Cull ('07, p. 396). We summarized in our former paper 

 ('14, III, pp. 453, 454) the various opinions in regard to the for- 

 mation of the macronuclear anlagen in Paramaecium, and showed 

 that the problem is not settled since Maupas and Klitzke believe 

 that four micronuclei and four macronuclear anlagen arise, three 

 of the micronuclei undergoing degeneration. Maupas states 

 definitely that four typical micronuclei are transformed into 

 macronuclear anlagen. In the animal in the process of re- 

 organization under discussion (fig. 19) this transformation of 

 micronuclei into macronuclear anlagen has been completed. 

 The anlagen are quite homogeneous, with the exception of a few 

 granules frequently dispersed in a circle. In preparations 

 stained with Delafield the anlagen show a diagnostic reddish 

 tinge which cannot be expressed without colored plates. (Com- 

 pare our present plates with those reproduced in colors in our 

 paper on Paramaecium aurelia). The chromatin bodies are 

 scattered throughout the cell in various stages of disintegration. 

 The next two figures (20 and 21) show only two micronuclei 

 and four macronuclear anlagen in each animal. This stage 

 may be interpreted as an animal in which two micronuclei have 

 degenerated, or as an animal after the degeneration of three 

 micronuclei and after the first somatic micronuclear division. 

 In our work we found it necessary to study the cytology of conju- 

 gation of our pedigreed races of Paramaecium caudatum with 

 particular reference to the fate of the four micronuclei which do 

 not form macronuclear anlagen. In our races it appears clear 

 that all four of the micronuclei do not persist and become dis- 

 tributed by the following two cell divisions as the definitive 

 micronuclei of the four completely reconstructed Paramaecium 

 cells. Figure 26 shows an exconjugant with clearly four macro- 

 nuclear anlagen and four micronuclei. Figure 27 gives a pedi- 

 greed animal, after the first cell division subsequent to conju- 

 gation, in which only one micronculeus is present. Figure 28 

 shows a pedigreed animal, after the second cell division subse- 

 quent to conjugation, with a macronucleus and micronucleus. 



